Double miter-box and calculator.



i Patnted` Mar. I3, 1900. P, F. McoNALD. DUUBLE MITER BOX AND CALCULATOR.

(Application led Oct. 13, 1899.)

` 2 sheets-sheet (No ModeL) No. 645,I20. Patented Mar. I3, |900. P. F. MGDDNALD.'

DOUBLE MIT'ER BOX AND CALCULATOR.

I (Application filed Oct. 13, 1899.)

(No Model.) 2 Sheets-Sheet z.

I? v J6 20 f/ o HE Nonms FE'rEns co, mmxj'mu., wAsmNGToN, u4 a PATRICK Ir. MoDoNALD, or DuNI/ionn, PENNSYLVANIA.

Douane MiTER-Box AND CALCULATOR.

SPECIFICATION forming part of Letters Patent No. 645,120,01aeea March 13, 1960'. Application filed October 13,1899. Serial No. 733,499. (No model.)

To @ZZ whom, it may concern;

Be itknown that I, PATRICK F. MCDONALD, a citizen of the United States, residing at Dunmore, in the county of Lackawanna and State of Pennsylvania, have invented certain new and useful Improvements in Double Miter-Boxes and Calculators, of which the following is a specication.

This invention relates to improvements in the form of double miter-boxes and calculators illustrated in my Patent No. 630,257, dated August 1, 1899; and it comprises certain novel features of construction by means of which the operation of the apparatus is facilitated.

In the accompanying drawings, Figure 1 is a plan view of the machine shown in my prior patent and embodying my present improvements. Fig. 2 is a front elevation of the same. Fig. 3 is a section on the line of Fig. 1. Fig. 4 is an enlarged detailed View of the sawguide and a portion of the standard. Fig. 5 is a section through the same centrally of the saw-guide. Figs. 6 and 7 are detailed views of the set-slide, and Fig. S is a perspective View showing the sliding scale.

Referring to the drawings, the letter A indicates a suitable base whose upper surface is= divided by scale-marks into two squares 1 and 2, the sides of which are twelve inches in length and which have the side 3 in common. These scales are suitably marked in inches, as shown in the drawings, the numerals upon the scales extending transversely of the base, running from rear to front, and those upon the front running in either direction from the center line. inscribed in these squares from the point 4 at the rear extremity of the side 3 as a center and with one quadrant in each of the squares 1 and vi). is a semicircular arc B, which is accurately divided and marked in degrees, as shown. The radius of this arc is the length of a side of these squares.

C designates a verticallyslotted center post or standard formed with a half-ball 5 at its lower end, which bears neatly but loosely in a hemispherical cup 6 in the base A, the center point of said cup and of the bearingba'll 5 coinciding with the point 4, which, as before stated, is the center from which the arc B is struck. The material of the `post adjacent to the ball is cut away, as indicated at 7, to permit the post to be moved to an angle of or approaching forty-five degrees without contacting with the base. A stud 8 projects upwardly from the end of the post and eX- tends through the space formed between parallel back plates E E, Whose upper and outer edges are cut to form an arc of one hundred and eighty degrees of the same radius as the arc B and having the same center. The post is guided between these back plates by means of a guide-plate F resting upon the post and having iianges 9V and 10, which extend upwardly on the outside of the back plates,` and a guide-block Gis vfitted within the guideplate and bears against the inner sides of the back plates. The guide plate and block are centrally perforated, as shown, to permit of the passage of the stud 8 therethrough, and a nut H is fitted to the stud 8 and adaptedto bear` upon the upper edges of the back plates to lock the post at any desired angle. The

.side plates are shown as being cut away at their central portion to permit the post or standard to assume an inclined position of forty-five degrees upon either side of the center. The arcuate rim portion of the plate E facing the front of the apparatus is marked with a scale 14 in degrees, as shown.

The above-described parts are substantially the same as the corresponding parts described in my prior patent, the only differences being in the details of the guides upon the upper end of the post. In said prior patent the saw guide is shown adjustable vertically upon the post; but the plates forming the guide were so arranged that they could not be inclined with reference to the post. For this reason when the post was inclined, as shown in Fig. 2, and then turned upon its axis the guide K, instead of being parallel with the base, would incline downwardly, as shown in dotted lines in said figure, so that diliiculty was experienced in handling the saw. To obviate this difficulty, I construct the saw-guide K of two independent plates, as shown in Figs. 4 and 5, which are arranged Within the slot 15 in the post and are held in position by means of setscrews 16, which pass through slots 17, arranged at right angles to the slot 15. The inner ends of the set-screws are provided with elongated heads 18, which fit within" depressions in the plates, as shown in Fig. 5, and

IOO

their outer ends are provided with nuts 19, which bear against semicylindrical frictionplates 20. These plates embrace the post, as shown, and their perpendicular faces abut against the saw-guide plates. It will be seen that by this construction the guides may be adjusted vertically upon the post by means of the set-screws and that they may be also tilted upward or downward, so that when the post is inclined and also turned upon its center the guides may be shifted, as indicated in Figs. 2 and 4, so as to be parallel with the base in all positions of the post. The saw within the guides therefore may always be held in the horizontal position.

A horizontal radial arm or rod L is secured. to the lower portion of the post C and adapted to sweep over the base A and its inscribed arc B, said arm or rod extending in the same direction as the saw-guide. By moving this arm so that it will extend over any given point on the arc B or over any point indicated upon the tangential scale-line 30 the saw-guide will be moved to the corresponding angle. Arranged upon said rod L is a guiding-nut M, having a stud 23, which iits within a perforation 24 in a setfslide N. The guiding-block M is provided with a set-screw 22, by means of which said guide may be secured upon the rod. It will be seen that when the set-screw is loosened the slide may be moved along in the guideway 26, the stud 23k turning in the aperture 24 as the slide moves. As shown lin the drawings, the slide N is formed with a downwardly-projecting flange 25, which iits within the guideway 26, formed between the front edge of the base and an angle-bar 27, which projects upwardly in front of the base. The body of the slide extends inwardly beyond the scale-line 30 and the center of the aperture 24is directly over the scale-line. In my former patent the aperture was arranged outside of the scaleline, so that the stud upon the guide M'did not center upon said line. In my present invention the center of the stud 23 comes directly over the scale-line 30, and the bore through which the rod L extends is centrally located over said stud, so that by simply moving the slide along within the guideway the center of the stud may be brought exactly over the desired point and the center line of the rod L will intersect the line 30 precisely at said point. The slide may be locked in this position by tightening the set-screw 22.

The set-slide is preferably made two inches in length, so that v its center is exactly one inch distant from either end. 'lo bring the center of the stud 23 directly over a given point, therefore, the ends of the slide are brought to the scale-marks one inch on either side of said point and thestud will be correctly positioned. To prevent wear of the scale, I place a strip of felt or other soft material upon the bottom of the set-slide to raise it above the scale.

In my former patent referred to I have shown a work-support O, extending the full length of the base, and aremovable scale P, which extends only over one of the squares. l have found it desirable to arrange the worksupport and movable scale in guideways, so that they may be moved across the base with facility and at the same time remain always parallel with its sides. To this end I have provided guideways 33 upon the ends, vwhich are formed by angle-irons 34, secured to the under side of the base, and I arrange flanges 32 upon the ends of the work-support and flanges 34a upon the movable scale, which fit within the guideways 33. The angle-irons 27 and 34 do not meet at the corners, so that the ends of the guideways are open and the parts which are movable in said guideways may be slid out through the open ends.

The scale P, as shown, is marked off into inches in either direction from the center, so that a cord or wire Q, connected at one end to a ring R, loosely mounted on the reduced portion 7 of the post C, may be stretched across said sliding scale on either side of the central line for the purpose of making calculations based on circles of less radius than that 'of the arc B. The wire Q is not necessary for the purpose of accurately adjusting the slide M, as in my former patent, but is mainly used for indicating upon the arc B the angle at which the post is to be adjusted upon the arcuate scale 14 and for making calcula-v tions upon circles of different radii, as stated.

Y Having described my improvements, what I claim, and desire to secure by Letters Pat-f ent of the United States, is-

. l. In a miter box or machine, the combina; tion with the base, a longitudinally-slotted guide-post mounted thereon,and means for securing said post in different rotary and angu= lar adjustments, of a saw-guide consisting of two independent plates secured to the post,- sa'id guide being adjustable bodily along the post, and also angularly in the plane of the slot.

2. In a miter box or machine of the kind described, the combinationwith the adjusts able post having two longitudinal slots formed therein at right angles to each other, of a sawguide consisting of independent plates arranged within one of said slots, set-screws ex tending through the other slot and connected to said guide-plates,friction-plates embracing the post, and nuts upon said set-screws adapted to bear against the friction-plates, substantially as described.

3. In a miter box or machine, the combination with a rectangular base having a sawguide post arranged at the center of one of its sides, and a scale-line 30 extending along the opposite side and having indicating-numerals reading in either direction from the central line, of a vset-slide movable along said scale-line, a radial arm secured to the post and a guide upon said arm, said guide being pivotally mounted in 'the set-slide and centered over said scale-line.

4. In a lniter boX or machine, the combination with a rectangular base having a guideits sides and a scale-line 30 extending along its opposite side, of a guideway adjacent to and parallel with said scale-line, a set-slide.

having a circular aperture Whose center is over the scale-line, and a flange tting Within the guideway, a guide having a stud fitting within said aperture, and a radial arm connected to the saw-guide post and extending centrally through said guide.

In testimony whereof I afIiX my signature in presence of two Witnesses.

PATRICK F. MCDONALD. Witnesses:

ROBERT WATSON, DAVID McDoNALD 

